[Hammarlund] Seeking Guidance to Repair HQ-170

[Kim Elmore]

Thanks, Al!

I’ve checked C11 and it’s fine and not leaky or shorted. I looked and yore absolutely correct: R9 is 1/2 W, not 1/4 W (1/4 W resistors weren’t generally available in 1959). All of the resistors are rated at no less than 1/2 W. 

Long ago, the WRL Globe Champ 350 I have burned up a carbon resistor and with it an 0A2 voltage regulator. Long story short what was a 1 W carbon comp resistor was in series with the regulator, and 1 W meant it got warm by design.

When carbon comp resistors get too warm, resistance decreases, increasing current and dissipation. That particular one in the Champ wound up “running away” resulting in a burned up resistor, an a 0A2 with a deformed envelope (it got that hot), and a burned up tube socket. 

I’m beginning to wonder if this is Déjà vu all over again, but in the receiver. In some pictures of the underside of the HQ-170 I’ve seen on restoration and radio museum sites, that particular resistor in the picture is clearly NOT original. That tells me I’m not the first. I have some 2 W metal film resistors I may solder in as a test. 

That said… I’m reluctant. That’s akin to replacing a blown fuse with one rated at a higher current. If something is truly wrong, I risk doing more damage if I simply plug in a more robust component, possibly damaging an IF transformer that is mode out of unobtainium. 

I’ve checked the side of the fuse that goes to the 6BE6 and I find no short to ground. The 6BE6 is NOT shorted either cold or in my Weston 981 Type 2 tube checker. 

73,

Kim N5OP

"People that make music together cannot be enemies, at least as long as the music lasts." -- Paul Hindemith

> On Mar 19, 2026, at 13:33, AW Parker <anchor at ec.rr.com> wrote:
> 
> Hi Kim,
>    Here are some thoughts which might be of help to you.
>    The skem I'm looking at shows R-9 as 1k 1/2w (not 1/4).  It's fed from the ~255v line to the plate of V2, 6BE6.  If the one in yours was a 1/4 watt, then it could just that which made it fail.  Use a 1/2w as replacement.  C-11 is a bypass to gnd, a .01mf ceramic disc.  Ceramic discs rarely get leaky, but it does happen.  If so here, it could be drawing extra current thru R-9.  With a replacement R-9 in there, you could measure the voltage drop across it and determine the wattage it dissipating.
> 73,
> Al, W8UT
> 
>> On 3/19/2026 10:25 AM, Kim Elmore via Hammarlund wrote:
>> I'm still flummoxed.
>> The incinerated resistor value is 1 k and it is R9: it was incinerated after serving well (as far as I know) since 1959 when my dad bought the receiver, new. The original manual, in which he notated repairs and any mods, is lost. I have determined that Revision 2 of the manual and schematic apply to this receiver and I have these. Based on the schematic whatever caused R9 to burn up resides somewhere between T1 and T2. I need to check C134, a 2 pF coupling capacitor between T1 and T2 but I simply cannot physically find it. While it's a long shot, I need to eliminate it as a cause (make sure it's not shorted) and I can't find it. I know what it should look like, but...
>> I've noticed in some images I see of the chassis underside (restoration pages, museum pages, etc.) R9 is clearly NOT original. This leads me to conclude that I'm not the first to experience this failure, but no one so far has apparently run across this, either. R9 is called out as 1/4 W and is on it's own single-lug terminal strip tat is riveted between and just to the right of T1 and T2 so as to avoid the array of trimmers that are the left of T1 and T2.
>> Any specific insights and experience with this particular failure are greatly appreciated!
>> 73,
>> Kim N5OP
>>> On 3/11/2026 8:12 PM, Kim Elmore via Hammarlund wrote:
>>> This is my first post to the group: I have an HQ-170 that has me flummoxed. It's has been "in the family" since my dad (W5JHJ SK 2007) purchased it new in May 1959. It, along with his WRL Globe Champion 350, comprised the first station I operated as a Novice in Fall 1970.
>>> 
>>> While I have a fair bit of experience working on the Champ, I have very little with the HQ-170: it simply has never needed much. My dad made no significant modifications to it aside from adding a modern 3- wire cord, an I.F. out port, and a plug for the mute circuit. A while back I turned on everything to let it warm up and was alarmed by a burning-paper smell. The source of the burning-paper odor was the '170. Upon removing it from the case, I discover half of an incinerated 1/4 W carbon resistor sitting in the bottom. A brief inspection reveals the other half remains soldered to a pin on T2, the transformer just to the rear of the 6BE6 1st converter (V3). The other side of the incinerated resistor is, or rather was, wired to terminal strip that has a lead to a pin on T6 (immediately behind V5, the second converter) that oddly appears to be vacant on the schematic. The linked image shows where the incinerated resistor was, circled in red. The resistor you see in the image is a out of my junk box and I put it there only so I don't lose track of where the incinerated resistor was.
>>> 
>>> A link to the image is here: https://drive.google.com/file/ d/1wD4ZJ8Y8QhLlgcJzYyYHEObE5YwCNjAo/view?usp=drive_link
>>> 
>>> I'm posting this in hopes that someone else has encountered the same problem and can guide me to a proper repair.
>>> 
>>> 73, N5OP
>>> 
> 
> 
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